The impact of organic carbon on soot light absorption


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Date

2021-02

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

The impact of organic carbon (OC) on the light absorption of soot is determined by discrete element modeling coupled with the discrete dipole approximation for computing the scattering of radiation by soot particles. The mass absorption cross-section (MAC) of soot is used widely to determine its light absorption. Typically MAC is obtained from the mass average refractive index of OC and elemental carbon (EC) with large C/H that make up mature soot. As such, MAC can be overestimated by a factor of 3 in fuel-rich flames where newly-formed young soot contains EC with small C/H and OC that predominantly scatters light reducing its absorption by soot. Here a relation for the soot refractive index is derived accounting for soot morphology, maturity and OC content through its band gap at wavelength, λ = 266–1064 nm. Using this relation, the MAC of soot containing OC (up to 50 wt%) is in excellent agreement with carbon black, graphene and soot data. This confirms that soot morphology, maturity and OC content greatly influence light absorption during characterization of in-flame and freshly-emitted soot by laser induced incandescence and light extinction, especially in fuel-rich flames, and need to be properly accounted for in the soot refractive index.

Publication status

published

Editor

Book title

Journal / series

Volume

172

Pages / Article No.

742 - 749

Publisher

Pergamon

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Organic carbon; Elemental carbon; Carbon black; Soot maturity; Refractive index; Mass absorption cross section

Organisational unit

03510 - Pratsinis, Sotiris E. (emeritus) / Pratsinis, Sotiris E. (emeritus) check_circle

Notes

Funding

182668 - Tailor-made Carbonaceous Nanoparticles by Multiscale Combustion Design (SNF)
163243 - Multifunctional nanoparticles for targeted theranostics (SNF)
170729 - Integrated system for in operando characterization and development of portable breath analyzers (SNF)

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